In harness racing horses pull sulkies containing drivers around a track utilizing a specified gait. In order to prevent a horse from becoming distracted by other horses and sulkies on the track beside him in the course of a race and to improve a driver's control over his horse the horse's head must be kept straight such that the animal has minimal freedom to move his head side to side. Side to side movement of a horse's head traditionally has been limited through utilization of a mechanical device known as a head pole. Such a device utilizes a relatively rigid rod having one end connected to a leather halter on the horse's head and the other end connected to a leather saddle mounted on the horse's back. The rear end of the head pole which connects to the saddle may be attached thereto by a strap having one end rigidly affixed to the saddle which passes through a slot in the end of the head pole and engages a buckle that is rigidly attached to the saddle. In order to enable a horse to move its head in fore and aft directions when the head halter has been attached to a head pole the head pole includes at least two concentric telescoping sections.
The front end of the head pole engages a metal ring attached to one side of the halter adjacent the horse's face. Traditional head poles have a piston at the front end thereof having a slot which opens into its outer surface. A movable spring loaded sleeve slides over the outer surface of the piston and in one position overlies the slot and in the other position exposes the slot. The sleeve is spring biased towards the first position to retain a ring once it has been placed in the slot.
In order for a person to attach or detach the front end of a head pole to a halter ring the operator must apply a lateral squeezing force to the outer surface of the sleeve and slide it against the action of the spring to the second position such that the lateral slot formed in the piston becomes exposed and the halter ring may be inserted or removed therefrom. To provide a person with a means for gripping the sleeve it has been a common practice to knurl the outer surface of the sleeve. However, despite the knurled surface formed on sleeve it remains a problem for a person to move a sleeve between the first and second positions when the sleeve is wet or cold because the person's ability to apply a lateral squeezing force on the sleeve becomes adversely affected under these conditions.